Process for vulcanizing rubber with condensation products of ammonia and aldehydes as accelerators



Patented July 29, 1924.

UNllEii stares h dfialiii [Parent raters.

SIDNEY M. CADWE LL, OF LEONIA, NEW JERSEY, ASSIGTNOR TO THE NitUGA'IUCK CHEMICAL CGMPANY, A CORPORATION OF CONNECTICUT,

I B-OCESS'FOB VULCANIZING RUBBER WITH CONDENSATION PRODUCTS OF AMMONIA AND .ALDEHYDES No Drawing.

Jersey, have invented certain new and usefulImprovements in Processes for Vulcanizing Rubber with Condensation Products of Ammonia and Aldehydes as Accelerators, of which the following is a full, clear, and exact description. v

This invention relates to vulcanization of rubber by which term as herein employed is included also balata' and gutta percha and rubber substitutes. It is more particularly directed to the vulcanization of rubber employing ammonia and open chain aldehydes and similar substances; and the products obtained therefrom.

This application is a continuation 'in part of my copending application Serial No. 473,345,,ifiled May 28, 1921, Patent No. 1,417,970.

In the British patent to Peachey, No. 7370 of 1914 the use of acetaldehyde ammonia'is set i'orth, but this accelerator is unstable and poisonous. It also imparts a color to vulcanized rubber and being crystalline is not easily incorporated therewith to form a homogeneous mass. Acetaldehyde ammonia is not a stable compound. Its physical characteristics as Well as its strength as an accelerator varies. with the time which. it has been stored, and its strength as an accelerator is of a relatively low order of magnitude.

It is accordingly an object of this invention to provide a process for vulcanization employing a series of compounds as'a-ccelerators which shall include non-poisonous stable materials of the type mentioned; materials which maybe used in white or light colored rubber without imparting an undesirable color thereto; which may be readily incorporated with the rubber to form a homogeneous mass; which shall be more active than the substance heretofore known of this type; which shall be substantially free from pre-vulcanization and which may be made from relatively inexpensive materials. Another object of the invention is to provide a vulcanized rubber having good aging properties. freedom from poisono us qualities and which shall have other desirable physical characteristics.

AS ACCELERATOBS.

Application filed May 15, 1922. Serial No. 561,021.

The invention accordingly consists in a process of treating rubber or similar materials which comprises combining the rubber with a vulcanizing agent and a re action product of an open carbon chain aldehyde having more. than .two and less than eight carbon atoms in the chain and ammonia, and vulcanizing the rubber. The

invention also includes the-products of such process.

In its preferred embodiment 100 parts of rubber, 10 parts of zinc oxide, 3 parts of sulphur and 0.5 parts of the condensation product of ammonia and heptaldehyde are mixed together by milling on rolls in the usual manner and vulcanization is accomplished by heating in a mold under 40 lbs. steam pressure for'60 minutes. The time of vul canization'will vary with the thickness of the rubber article undergoing vulcanization. In the examples given the thickness of the materials is generally v The reaction product of ammonia and heptaldehyde may be prepared by mixing equal molecular weights. of ammonia, as aqua ammonia and heptaldehyde, and heating to 130 0.

-I3.t81121l$ having properties similar to that of the condensation. product of ammonia and heptaldehyde are .as follows: propionaldehyde, ammonia, cinnamylaldehyde ammonia, iso valeraldehyde ammonia.

It will be observed that the accelerators except the known accelerator acetaldehyde ammonia listed above include an open car desired to produce various compounds. The

quantity of the reaction product employed may vary from 0.2-1 part or more. 0.2 parts is ordinarily used when employing heptaldehyde ammonia as indicated.

Although in the examples given above, the aldehyde ammonia compounds are indicated. as being milled while in the form of this compound with rnl'iber, it will be obvious that the invention set forth in my copcndi'ng' application Serial No. 441,6 91, filed February l, 1921 may be followed and that the ii'igredients. making up the aldehyde ammonia condensation product may be added separately. For example the following procedure may be carried out: 100 parts of rubber. 10 parts of zinc oxide, 3 parts oi sulphur and It parts of heptaldehyde may be combined by milling. The mixture may then be exposed to ammonia for minutes at (F, ()r if desired the ammonia may be brought. into contact with the mixture at ordinary temperature (70" F.) and allowed to remain in contact therewith for hours. The rubber is subsequently vulcanized in the usual manner for minutes under =10 lbs. steam pressure.

In acrordam'ze with tensile strength tests, it has been observed that the n'et'erred member of this group is beptahlehyde ammonia. In its use in rubber this material also has other highly desirable properties. lt is substantially non-toxic. It does not impart a color to rubber with which'it is vulcanized. it is an oil and may be'rcadily incorporated in the rubber to form a homogeneous mixture. It: exhibits substantially no tendency to prcvulcanize upon milling at the ordinary milling tenu'ieratures. llcptaldehyde ammonia is substantially stable and does not decompose upon being stored under-ordinary conditions. When manpared with aretaldehyde ammonia it is approximately four times as powerful as aeetaldehyde ammonia. The various members in the table above other than heptaldel'iyde ammonia (and excepting acetaldehyde ammonia) have one or more of the valuable 'n'oywrfles ascribed to lieptaldellydc ammonia and are accordingly valuable.

it is pointed out that in the emulensatcsot aldehydcs with ttlllll ltfllltl. more than one reaction product may be formed and accelerating action may be due in part at least; to one or more of these products. it will be understoodaccordingly that the appended claims are intended to cover rea tion products containing either the simple condensation of aldehyde and ammonia or one of a different charm-tor or both.

twill be observed that the products listed above are in general con'ibinations of ammonia with straight chain aldeliydesone of which in the case of cinnamylaldehydc has benzene ring linked to the chain and having the carbon.

atoms of the st raight; chain.

As many apparently widely different em: bodiments of this invention may be made without departing .t'rom the spirit thereof, it will be understood that I do not intend to limit myself to the specific embodiment herean aldehvdc group linked to heptaldehyde.

comprises combining the rubber with avulcanizing agent and a reaction product of an open carbon chain aldehyde having more than two carbon atoms and ammonia, and vulcanizing the rubber.

2. A process of treating rubber which comprises combining the rubber with a vulcanizing agent and a reaction product of an aldehyde having seven carbon atoms in a straight hydrocarbon chain and ammonia, and vulcanizing the rubber.

I). A process of treating rubber which comprises combining the rubber with a vulcaniz ing agent and the reaction product of heptaldehyde and ammonia, and vulcanizing the rubber. I

4. A process of treating rubber which comprises combining the-rubber with a vulcanizing agent, a bivalent metal and the reaction product of hcpt'aldehyde and ammonia, and vulcanizing the rubber.

5. A process of treating rubber which comprises combining the rubber with a bivalent metal, sulphur, and the reaction product of ammonia and heptaldehyde, and vulcanizing the rubber.

6. A'process of treating rubber which comprises combining the rubber with zinc in combination, sulphur and heptaldehyde ammonia, and vulcanizing the rubber.

7. A. vulcanized rubber derived from rubber combined with a vulcanizing agent and a reaction product of an open carbon chain aldehyde having more than two carbon atoms and ammonia,

8.- A vulcanized rubber derived from rubber coml'iined with a vulcanizing agent and a1 reaction product of an aldehyde having seven earlumatoms in a straight hydrocarbon chain and ammonia.

9. A vulcanized rubber derived from rubber combined with a vulcanizing agent and the reaction product of lieptaldehyde and ammonia.

it). A

11. Ayulcimized'i'ubbcr derived tromrubher combined with a bivalent metal, sulphur, and the reaction product of ammonia and 12. A vulcanized rubber derived from rubber con'ibined with zinc in combination, sulphur and he 'italdehyde an'unoniar- Signed at'New York, New York, this 13th day of May, 1022.

- SIDNEY M. CA'DWELL.

vulcanized rubber derived from 1,11. rubber combined with a vulcanizingnageng 

